Tools dig, cut and fly to success

Tom Shelley reports on some interesting ideas from Interplas 2002, especially those revealed in the Eureka-sponsored Designing in Plastics Technical Centre Functionality and sales performance can be dramatically improved with the simple incorporation of plastics into product designs; even in items as mundane as spades and scissors. Andy Toward, director of Rotherham-based Advanced Product Development, told Eureka that local companies often approached to create differentiation – allowing their products to gain an improved position in the market. One of the co-sponsors of the Designing in Plastics Technical Centre, he was able to demonstrate a greatly improved garden spade, developed for Spear and Jackson and an improved pair of hairdressing scissors, developed for Chapman and Hill. The technical innovation in the spade is a cellular EVA foam pad shock absorber in the shank, but what really sets it apart is its much larger handle, with grips on the sides. He said that ergonomic studies showed that users often thrust spades downwards two-handed so it is useful to design handles to accommodate this. Similarly, the new hairdresser's scissors, which sell for around £200 each, incorporate a shock absorber to reduce impact when they close, an adjustable tensioning joint, pop-out inserts for finger rings (to accommodate different finger sizes), replaceable blades, a choice of locations for the pins on the outsides and twistable finger rings. These improvements, all achieved with the help of polymers, have apparently increased sales several times over, achieving a significant penetration into the estimated 190,000-pairs-per-annum market in the UK alone. Distrupol, on its stand at Interplas, revealed that it had helped a West Midlands builder develop a mostly plastic cutting product for tapering plastic pipes – facilitating pipe joining. PipeMate is the brainchild of West Midlands builder Dave Higgs. He saw a need to bevel the ends of four inch building pipes and remove cutting strands to make leak-free joints. In order to develop it, he took his idea to Sutton-in-Ashfield moulder, AAC. Distrupol, in turn, helped AAC select and fine tune the grades of materials needed for the various components. In operation, the PipeMate works like a king-sized pencil sharpener, although it is still small enough to carry out and use on a building site. It uses an impact resistant ABS grade for the outer body and Delrin (Acetal) for the internal mechanism. The interior cutting edge is a square block of solid carbide. Typically selling for just under £60 each, Jewsons stock it and target markets include ground workers, roofers and plumbers. AAC aims to produce nearly 100,000 PipeMates per year. Staying on the subject of pipes and hollow sections, Matt Schoepfer of Schulman Polymers gave a seminar at the Designing in Plastics Technical Centre on the virtues of water (as opposed to gas) injection moulding. Although the process was patented by Hobson in the UK in 1938, nobody took much notice of it until it was 're-invented' by IKV-Aachen in 1999. Its advantages include a reduction in cycle times and it offers the capability to manufacture parts with thinner wall thicknesses. The reduced cycle time – one quarter to one fifth in the case of some polypropylene parts – comes from the internal cooling effect of the water. The thinner walls are possible because water is not compressible, and it is possible to meter out the internal volume of a hollow part very accurately. One of the products currently produced by this method is a Volvo door handle. Inner surfaces are also said to be improved, especially with fibre reinforced grades. It is said to even be possible to water injection mould nylon, provided careful choice is made of grades and operating conditions. Mowers fly Consulting with John Brenchley of Distrupol, during a seminar on high temperature plastics, gained some insight into the particular problem of the melting mower (Editor's Comment, page 3, September 2002) and possible solutions. Plastics capable of surviving a motor overheat do exist aplenty, but are, in the main, expensive. Brenchley suggested polypropylene to be an appropriate material for the bulk of a garden mower, with possible use of one of the cheaper grades of nylon for the sub-frame. The trick, it would seem, is to ensure that the power cuts out just before the motor gets hot enough to cause the plastic that it is in contact with to soften. Careful attention has to be paid to the relevant heat deflection temperature and temperature under load, two measured quantities that are not only different, but in neither case apply exactly to real-world conditions. Expertise is, apparently, continually being gathered in the use and application of both old and new plastic-based materials, and what designers can get away with and what they can't. Brenchley referred to the changing designs of plastic kettles, irons and automotive parts. The other alternative, of course, is to use a sub frame made of metal, attached to plastic upper parts. What the ideal solution is with the mower, we do not know, except we expect to have a chance to test it now that Flymo has promised to replace the one that was the subject of the comment article. It may or may not be a coincidence that IBM has just announced that the Electrolux Group, which owns Flymo, is purchasing 700 licences of CATIA V5 to improve its design process and that the Group has announced plans to complete a total enterprise integration of Product Lifecycle Management technologies, including the creation of digital factories. Acting on the fact that the Samsung product mentioned in the same comment article was insured, the company's agent promptly replaced one of the failed A300 phones with its successor, which has a much more strongly designed hinge. As he did so, he apologised that the original design was no longer in production, but pointed out that the successor has a whole host of improvements including better software and a built-in camera. It is nice to know that all the companies mentioned have shown themselves to be determined to solve their design problems. Companies that just hope their problems will go away, usually have their wishes fulfilled – along with the departure of their customers. profits and businesses. advanced product development centre Distrupol Schulman Polymers IBM UK